SR1 RNA

In molecular biology, the SR1 RNA is a small RNA (sRNA) produced by species of Bacillus and closely related bacteria.{{cite journal|vauthors=Gimpel M, Preis H, Barth E, Gramzow L, Brantl S |title=SR1—a small RNA with two remarkably conserved functions.|journal=Nucleic Acids Research|date=October 13, 2012|pmid=23034808|doi=10.1093/nar/gks895|volume=40|issue=22|pmc=3526287|pages=11659–11672}} It is a dual-function RNA which acts both as a protein-coding RNA and as a regulatory sRNA.

SR1 RNA is involved in the regulation of arginine catabolism. SR1 RNA binds to complementary stretches of ahrC mRNA (also known as argR and inhibits translation.{{cite journal|vauthors=Heidrich N, Moll I, Brantl S |title=In vitro analysis of the interaction between the small RNA SR1 and its primary target ahrC mRNA.|journal=Nucleic Acids Research|year=2007|volume=35|issue=13|pages=4331–4346|pmid=17576690|doi=10.1093/nar/gkm439|pmc=1935000}}{{cite journal|vauthors=Heidrich N, Chinali A, Gerth U, Brantl S |title=The small untranslated RNA SR1 from the Bacillus subtilis genome is involved in the regulation of arginine catabolism.|journal=Molecular Microbiology|date=October 2006|volume=62|issue=2|pages=520–536|pmid=17020585|doi=10.1111/j.1365-2958.2006.05384.x|doi-access=free}} AhrC endodes an arginine repressor protein which represses synthesis of arginine biosynthetic enzymes and activates arginine catabolic enzymes via regulation of the rocABC and rocDEF operons.{{cite journal|vauthors=North AK, Smith MC, Baumberg S |title=Nucleotide sequence of a Bacillus subtilis arginine regulatory gene and homology of its product to the Escherichia coli arginine repressor.|journal=Gene|date=August 1, 1989|volume=80|issue=1|pages=29–38|pmid=2507400|doi=10.1016/0378-1119(89)90247-3}}{{cite journal|pmid=1312212 | volume=6 | issue=2 | title=Purification and initial characterization of AhrC: the regulator of arginine metabolism genes in Bacillus subtilis |date=January 1992 | pages=267–275 | doi=10.1111/j.1365-2958.1992.tb02008.x | journal=Mol. Microbiol.| vauthors=Czaplewski LG, North AK, Smith MC, Baumberg S, Stockley PG | s2cid=3219261 }}{{cite journal|vauthors=Dennis CA, Glykos NM, Parsons MR, Phillips SE |title=The structure of AhrC, the arginine repressor/activator protein from Bacillus subtilis.|journal=Acta Crystallographica Section D|date=March 2002|volume=58|issue=Pt 3|pages=421–430|pmid=11856827|doi=10.1107/s0907444901021692}}

In addition to acting as a sRNA, SR1 also encodes a small peptide, SR1P. SR1P binds to glyceraldehyde-3-phosphate dehydrogenase (GapA) and stabilises the gapA operon mRNAs.{{cite journal|vauthors=Gimpel M, Heidrich N, Mäder U, Krügel H, Brantl S |title=A dual-function sRNA from B. subtilis: SR1 acts as a peptide encoding mRNA on the gapA operon.|journal=Molecular Microbiology|date=May 2010|volume=76|issue=4|pages=990–1009|pmid=20444087|doi=10.1111/j.1365-2958.2010.07158.x|url=https://hal.archives-ouvertes.fr/hal-00552633/file/PEER_stage2_10.1111%252Fj.1365-2958.2010.07158.x.pdf|doi-access=free}}

SR1 expression is regulated by CcpA and CcpN.{{cite journal|vauthors=Licht A, Preis S, Brantl S |title=Implication of CcpN in the regulation of a novel untranslated RNA (SR1) in Bacillus subtilis.|journal=Molecular Microbiology|date=October 2005|volume=58|issue=1|pages=189–206|pmid=16164558|doi=10.1111/j.1365-2958.2005.04810.x|s2cid=29961832 }}{{cite journal|pmid=19726675 | doi=10.1074/jbc.M109.033076 | volume=284 | issue=44 | title=The transcriptional repressor CcpN from Bacillus subtilis uses different repression mechanisms at different promoters | pmc=2781557 |date=October 2009 | pages=30032–30038 | journal=Journal of Biological Chemistry| vauthors=Licht A, Brantl S | doi-access=free }}